matplotlib子批中的行和列标题

有几种方法可以做到这一点。简单的方法是利用图的y标签和标题,然后使用 fig.tight_layout() 为标签腾出空间。或者,您可以使用 annotate 然后半手动为其腾出空间。

如果轴上没有y标签,很容易利用第一行和第一列轴的标题和y标签。

import matplotlib.pyplot as plt

cols = ['Column {}'.format(col) for col in range(1, 4)]
rows = ['Row {}'.format(row) for row in ['A', 'B', 'C', 'D']]

fig, axes = plt.subplots(nrows=4, ncols=3, figsize=(12, 8))

for ax, col in zip(axes[0], cols):
    ax.set_title(col)

for ax, row in zip(axes[:,0], rows):
    ax.set_ylabel(row, rotation=0, size='large')

fig.tight_layout()
plt.show()

如果您确实有y标签,或者如果您更喜欢一点灵活性,可以使用 注释 放置标签。这更复杂,但允许您除了行和列标签之外,还可以使用单独的绘图标题、ylabels等。

import matplotlib.pyplot as plt
from matplotlib.transforms import offset_copy


cols = ['Column {}'.format(col) for col in range(1, 4)]
rows = ['Row {}'.format(row) for row in ['A', 'B', 'C', 'D']]

fig, axes = plt.subplots(nrows=4, ncols=3, figsize=(12, 8))
plt.setp(axes.flat, xlabel='X-label', ylabel='Y-label')

pad = 5 # in points

for ax, col in zip(axes[0], cols):
    ax.annotate(col, xy=(0.5, 1), xytext=(0, pad),
                xycoords='axes fraction', textcoords='offset points',
                size='large', ha='center', va='baseline')

for ax, row in zip(axes[:,0], rows):
    ax.annotate(row, xy=(0, 0.5), xytext=(-ax.yaxis.labelpad - pad, 0),
                xycoords=ax.yaxis.label, textcoords='offset points',
                size='large', ha='right', va='center')

fig.tight_layout()
# tight_layout doesn't take these labels into account. We'll need 
# to make some room. These numbers are are manually tweaked. 
# You could automatically calculate them, but it's a pain.
fig.subplots_adjust(left=0.15, top=0.95)

plt.show()

以上答案有效。只是在答案的第二个版本中,你有:

for ax, row in zip(axes[:,0], rows):
    ax.annotate(col, xy=(0, 0.5), xytext=(-ax.yaxis.labelpad-pad,0),
                xycoords=ax.yaxis.label, textcoords='offset points',
                size='large', ha='right', va='center')

而不是:

for ax, row in zip(axes[:,0], rows):
    ax.annotate(row,xy=(0, 0.5), xytext=(-ax.yaxis.labelpad-pad,0),                    
                xycoords=ax.yaxis.label, textcoords='offset points',
                size='large', ha='right', va='center')

基于Joe Kington's answer ,我提出了一个可以在代码库中重用的函数:

它接受以下参数:

• fig :包含要处理的轴的图形
• row_headers , col_headers :要作为标头的字符串序列
• row_pad , col_pad : int 调整填充的值
• rotate_row_headers :是否将行标题旋转90°
• **text_kwargs :转发至 ax.annotate(...)

此处为函数,示例如下:

import numpy as np

def add_headers(
    fig,
    *,
    row_headers=None,
    col_headers=None,
    row_pad=1,
    col_pad=5,
    rotate_row_headers=True,
    **text_kwargs
):
    # Based on https://stackoverflow.com/a/25814386

    axes = fig.get_axes()

    for ax in axes:
        sbs = ax.get_subplotspec()

        # Putting headers on cols
        if (col_headers is not None) and sbs.is_first_row():
            ax.annotate(
                col_headers[sbs.colspan.start],
                xy=(0.5, 1),
                xytext=(0, col_pad),
                xycoords="axes fraction",
                textcoords="offset points",
                ha="center",
                va="baseline",
                **text_kwargs,
            )

        # Putting headers on rows
        if (row_headers is not None) and sbs.is_first_col():
            ax.annotate(
                row_headers[sbs.rowspan.start],
                xy=(0, 0.5),
                xytext=(-ax.yaxis.labelpad - row_pad, 0),
                xycoords=ax.yaxis.label,
                textcoords="offset points",
                ha="right",
                va="center",
                rotation=rotate_row_headers * 90,
                **text_kwargs,
            )

以下是在标准网格上使用的示例(没有轴跨越多行/列):

import random
import matplotlib.pyplot as plt

mosaic = [
    ["A0", "A1", "A2"],
    ["B0", "B1", "B2"],
]
row_headers = ["Row A", "Row B"]
col_headers = ["Col 0", "Col 1", "Col 2"]

subplots_kwargs = dict(sharex=True, sharey=True, figsize=(10, 6))
fig, axes = plt.subplot_mosaic(mosaic, **subplots_kwargs)

font_kwargs = dict(fontfamily="monospace", fontweight="bold", fontsize="large")
add_headers(fig, col_headers=col_headers, row_headers=row_headers, **font_kwargs)

plt.show()

如果某些轴跨越多行/列,那么正确分配行/列标题就不那么简单了。 我没有设法从函数内部进行排序,但要小心给定的 行标头(_H) 和 冷水龙头 参数足以使其轻松工作:

mosaic = [
    ["A0", "A1", "A1", "A2"],
    ["A0", "A1", "A1", "A2"],
    ["B0", "B1", "B1", "B2"],
]

row_headers = ["A", "A", "B"]  # or
row_headers = ["A", None, "B"]  # or
row_headers = {0: "A", 2: "B"}

col_headers = ["0", "1", "1", "2"]  # or
col_headers = ["0", "1", None, "2"]  # or
col_headers = {0: "0", 1: "1", 3: "2"}

fig, axes = plt.subplot_mosaic(mosaic, **subplots_kwargs)
add_headers(fig, col_headers=col_headers, row_headers=row_headers, **font_kwargs)
plt.show()